Unbalanced state affected my mastery (9)
I believe the answer is:
asymmetry
'unbalanced state' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'affected my mastery' is the wordplay.
'affected' is an anagram indicator.
'my'+'mastery'='mymastery'
'mymastery' is an anagram of 'ASYMMETRY'.
Can you help me to learn more?
(Other definitions for asymmetry that I've seen before include "with different faces" , "displays a lack of regularity" , "Irregularity" , "Lack of similarity between two parts or halves" .)